Welcome to the Microsoft .NET Framework version 3.5. The .NET Framework is an integral Windows component that supports building and running the next generation of applications and Web services. The key components of the .NET Framework are the common language runtime (CLR) and the .NET Framework class library, which includes ADO.NET, ASP.NET, Windows Forms, and Windows Presentation Foundation (WPF). The .NET Framework provides a managed execution environment, simplified development and deployment, and integration with a wide variety of programming languages. For a brief introduction to the architecture of the .NET Framework, see .NET Framework Conceptual Overview. For a discussion of .NET Framework version 3.5 and its relationship to previous versions of the .NET Framework, see .NET Framework 3.5 Architecture.

Quick Technology Finder

Provides a table of links to the main technology areas of the .NET Framework.

What's New in the .NET Framework

Describes key features that have been added or modified in the latest versions of the .NET Framework.

Overview of the .NET Framework

Describes key .NET Framework concepts such as the common language runtime, the common type system (CTS), cross-language interoperability, managed execution, assemblies, and security.

.NET Framework Class Library

Supplies syntax, code examples, and related information for each class contained in the .NET Framework namespaces.

Guidelines and Best Practices

Provides a list of links, categorized by technology, to Guidelines and Best Practices topics.

How-to and Walkthrough Directory

Provides a list of links, categorized by technology, to How-to and Walkthrough topics.

.NET Framework Samples

Provides samples on various aspects of the .NET Framework and the .NET Compact Framework.

Security in the .NET Framework

Provides information about the classes and services in the .NET Framework that facilitate secure application development.

Core Development Technologies

Explains common programming tasks that apply to a range of .NET Framework applications. Includes topics such as accessing data, file and stream I/O, configuration, encoding, deployment, and debugging.

Advanced Development Technologies

Provides information about sophisticated development tasks and techniques in the .NET Framework.

ASP.NET Web Applications in the .NET Framework

Provides instructive overviews and detailed, step-by-step procedures for creating ASP.NET applications, Web Forms, and Web services.

Windows-based Applications

Provides information about working with Windows Forms and console applications.

Windows Presentation Foundation

Provides information about developing applications using Windows Presentation Foundation (WPF).

Windows Communication Foundation for Applications

Provides information on the Windows Communication Foundation (WCF) programming model for building service-oriented applications.

.NET Compact Framework

Introduces the .NET Framework-based, hardware-independent environment for running applications on resource-constrained computing devices.

.NET Framework General Reference

Provides reference information related to the .NET Framework. Includes sections on languages and compilers, tools, technical references, and a glossary of terms.